The prior art discloses a number of different fence wire attachment devices for securing fence wires to a fence post while allowing some limited horizontal motion of the fence wires, i.e., motion of the wire in the plane of the fence or along the fence line. Although fences serve as effective borders between property parcels and restrain livestock within the fenced area, crossing the wire fence when desired is problematic. Whether for work or pleasure, the crossing effort is cumbersome, hazardous and impossible for some people. The crossing effort is exacerbated if one is carrying a tool or firearm. Further, it is significantly more difficult and hazardous to move equipment and harvested animals across the fence line.
To cross the prior art fence the person must climb over the top fence wire (hazardous), climb between two successive fence wires (hazardous, awkward and cumbersome), climb under the lowest fence wire, cut the fence wire (expensive and not cost effective) or pass through the nearest gate (neither timely nor cost effective). Thus the person may decide not to cross the fence at all.
If there is sufficient slack in the fence wire, the application of a downwardly-directed force to the upper fence wire(s) moves it (them) downwardly as the slack is taken up. Thus the wire must be displaceable along its length as the wire is moved vertically. Slack in the wire accommodates such upward or downward displacement of the wire(s). Vertical motion of the wire is prevented or at a minimum constrained if the wire cannot be displaced along its length, such as if the fence wire is rigidly secured to each fence post.
Prior art devices for attaching the fence wire to the post may not allow such displacement of the fence wire along the fence line, may not allow vertical displacement of the fence wire or may not allow both. In either case, these devices prevent vertical movement of the fence wire. Instead, such attachment devices are intended to securely and tightly hold the fence wire in a snug or taut condition to the fence posts. If the wire is fixedly attached to the fence posts on either side of the crossing point, it may be difficult to vertically displace the fence wire as there is little or no slack to be taken up. Advantageously stringing the fence wires in the taut condition allows them to resist external forces exerted on the fence wires, such as snow loads and contact with animals and farm implements. But without slack, the wires are not easily moved vertically. Clearly, fixed attachment of the fence wire to the fence posts impedes vertical movement of the fence wire. Releasing the fence wire from the taut condition to cross the fence is a time-consuming task that may require the use of special tools. The fence wire must then be returned to its taut condition.
The above described difficulties in releasing the fence wires to permit downward or upward displacement of one or more upper fence wires also applies to the upward displacement of the lower fence wires to permit one to crawl under the fence wires.
In accordance with common practice, the various described features are not drawn to scale, but are drawn to emphasize specific features relevant to the invention. Like reference characters denote like elements throughout the figures and text.